Marine ecologists have shown how noise pollution is changing the behaviour of marine animals - and how its elimination will significantly help build their resilience. Laura Briggs reports.

Building up a library of sound from marine creatures including cod, whelks and sea slugs is important to helping build resilience in species affected by noise pollution, according to Exeter University's Associate Professor in Marine Biology and Global Change Dr Steve Simpson.

Human noise factors including busy shipping lanes, wind farms and water tourism can all impact on the calls of various species - including cod which relies on sound for finding a mate with their "song".

In certain areas it has even been discovered that cod have changed the frequency of their song to deal with the impacts of noise pollution. Different coral reefs will also make different noises to attract different varieties of fish. Findings also show that fish will only respond to sounds they are familiar with.

Dr Simpson says: "Over the last 200 years the marine soundscape has changed due to human activity, which means animals that have developed over millions of years are having to adapt to survive these changes.

"If you live half your life in the dark, and if you live in murky waters, sound is really important and of course it travels far better under water than through light.

"It is a better communication channel to find both prey and predators and then avoid them so it's really key for marine animals, from whales and dolphins to crabs and coral."

As a NERC Knowledge Exchange Fellow, Dr Simpson and his colleagues have been compiling a library of sounds from fish and marine invertebrates to further understand its importance.

Listening to the sounds made by a range of fish species, including crab, sea slugs and whelks and by recording the whole marine ecology system, their findings show that the behaviour of species is altered where noise pollution is a factor.

"Looking at the data, we realise that sound has real complexity. For animals like cod their call is particularly important during mating time. When fish are trying to get ahead in the mating game they don't have plumage or facial expressions to rely on, so sound is the way they make themselves as attractive as possible."